docs: def find_first_available_template(self, template_name_list):
          """
          Given a list of template names, find the first one that actually exists
          and is available.
          """
          if isinstance(template_name_list, six.string_types):
              return template_name_list
          else:
              # Take advantage of fluent_pages' internal implementation
              return _select_template_name(template_name_list)